warning message

Hi,
In running R for a two trait model I get the following
warning message
Warning message:
In sqrt(s2 * object$vcoeff$random) : NaNs produced

The heritability estimate is clearly wrong, as indicated by
the program run for a single trait, which does not give this
message.

Can anyone tell me what the message refers to and how I
might resolve the problem?
Thanks
Derek
Derek Roff,
Department of Biology,
University of California,
Riverside,
CA 92521
USA
Received on Fri Nov 05 2007 - 11:25:45 EST